1. Technical Field
The present invention relates to the field of online multi-phase flow measurement. Namely, an online multi-phase flow meter for an oil well production pipeline or an oil transportation pipeline that measures the volumetric flow quantities of gas, oil, and water contained in a multi-phase mixture.
2. Description of the Related Art
The “background” description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description which may not otherwise qualify as prior art at the time of filing, are neither expressly or impliedly admitted as prior art against the present invention.
Increasingly, the measurement of multi-phase flow is a focus of attention in the oil and gas industry. An oil well produces a mixture of oil, water, and gas in normal production. In order to assess the productivity of an oil well it is necessary to know how much of these three phases: oil, water, and gas, is being produced. Accordingly, multi-phase flow meters are required to operate and manage oil fields and reservoirs. A number of multi-phase flow meters (MPFMs) have been developed; however, conventional MPFMs are highly sophisticated devices and expensive.
Conventionally, industry utilizes three-phase or two-phase separators to separate the multi-phase fluid mixture into distinctive phases. Three-phase separators separate the multi-phase fluid mixture into distinctive phases—gas, free water, and an oil/water emulsion. Thereafter, separate flow meters may measure the respective flow rates of the outgoing streams of oil, water, and gas. Also, an on-line “cut” meter determines the water content of the emulsion stream. The two-phase separators operate similarly to the three-phase separators except that the free water stream is omitted.
Due to the complex nature of crude oil mixtures, the accurate measurement of multi-phase flow rates is challenging. To measure the flow rates of multi-phase fluids, the phase fraction and phase velocity measurement devices are generally used. For instance, Venturi meters are frequently used to measure the velocity of the mixture. However, conventional two phase measurement requires separation of the two phases (oil and water), which results in the interruption of the continuous industrial process.
Ultimately, conventional test separators are relatively large in physical size, expensive to construct, and require an abundance of ancillary pressure control and flow regulating equipment. Accordingly, users of this approach do not provide the separators for an individual oil well. Instead, a single test separator services a group of wells. Each individual well is placed “on test” for a relatively short period of time, and its production is determined. After the well is removed from test, it is assumed that the production from the well does not vary substantially until the well is again placed on test.
To overcome the deficiencies of the prior art, the present invention provides a simple, easy to operate online multi-phase flow meter that continuously and accurately measures gas, oil, and water quantities on line for an individual oil well, a group of wells in oil field, or a transportation pipeline.